public class code {
    public static void main(String[] args) {
        int num = 8;
        int a = 1;
        int b = 1;
        int sum = 0;
        switch(num){
            case 1:
            case 2:
                System.out.println(1);
                break;
            default:
                for (int i = 3; i <= num;i++) {
                    int c = a + b;
                    a = b;b = c;
                    sum
                     = c;
                }
                System.out.println(sum);
                break;
        }

    }
}
